1. Field of the Invention
This invention relates in general to electrical raceway supports, and in particular to supports used for supporting vertical raceways extending from electrical control cabinets of industrial machinery.
2. Prior Art
Within the electrical field there exists requirements for electricians to install and support various diameters, types and quantities of vertical raceways to industrial machinery and associated electrical equipment.
These raceways serve as the primary enclosed channel for electrical conductors that provide electrical power to the machines and equipment. The various diameters of raceways mentioned above relate to, but not limited to the following trade sizes, 1/2", 3/4",1", 11/4", 11/2", 2",21/2", 3", 31/2, and 4". The various types of raceways as mentioned above consist of, but not limited to rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquid tight flexible conduit, flexible metal conduit, electrical nonmetallic tubing, and electrical metallic tubing.
The 1990 National Electrical Code requires all types of raceways regardless of diameter to be firmly supported after installation. To give the reader a better understanding of the art to follow, it is important for the reader to fully understand the requirements for supporting the various types of raceways as per the National Electrical Code 1990. The Code states "The following types of raceways shall be supported within three (3) feet of electrical control cabinets, rigid metal conduit, rigid nonmetallic conduit, intemediate metal conduit, electrical nonmetallic tubing and electrical metallic tubing." The code also states "The following types of raceways shall be supported within one (1) foot of electrical control cabinets, liquidtight flexible conduit, flexible metallic conduit and flexible metal conduit."
The purpose of these strict supporting requirements is a safety measure to insure the raceway will not separate from its connection point, losing continuity of the raceway system and losing an effective equipment grounding path; which is necessary to protect machine operator/operators against possible electrical shock or even electrocution.
Various means and methods have existed in prior arts for supporting conduit. Tehen Et. Al., U.S. Pat. No. 4,259,542 teaches a poke-through electrical fitting, and Beaton U.S. Pat. No. 858,140 teaches hangers for gas pipes, which has a slot for adjustment. What ever the precise merits, features and advantages of the above cited references, none of these achieve or fulfills the purpose of the conduit support bracket the present invention.
Currently within industry electricians are called upon to install and relocate existing machinery within industrial work places. Each time a machine is relocated, or a new machine is installed it will require electrical power for its operation. Within the industrial work areas machines and other equipment are usually set in open bay areas with no structural members close by for supporting electrical raceways. Normally the only structural members available is the high bay steel located approximately twenty (20') above the finished floor. This poses a difficult situation for the electrician because he does not currently have a simple means of meeting the supporting requirements of the 1990 National Electrical Code, article 346-12, Exception No. 2 which states; "The distance between supports shall be permitted to be increased to twenty (20') feet for exposed vertical risers from industrial machinery provided that the conduit is firmly supported at the top and bottom of the riser, and no other means of intermediate support is readily available." Often times the requirement exists for electricians to install two vertical raceways to one electrical control cabinet of the machine. The two raceways may be the same trade size diameter, example 1/2" and 1/2", or they may consist of two different diameters, example 1/2" and 4", often these two raceway combinations mentioned will be of different types, of conduit.
An example being rigid metal conduit, the other being flexible metal conduit both of which have different supporting requirements as outlined in the National Electrical Code. Another situation frequently encountered by an electrician is installing two raceways to industrial machine control cabinets with one raceway being vertical and the other being horizontal both of which will have to be supported.
Currently in industry there does not exist any known vertical raceway support bracket capable of being bolted directly to a machine control cabinet and having the versatility of securing one or two vertical raceways to the support bracket or a combination of one horizontal and one vertical raceway, and further accommodate and support the various types of rigid metal conduit rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible conduit, flexible metallic conduit, flexible metal conduit, electrical nonmetallic tubing, and electrical metallic tubing and sizes 1/2", 3/4", 1", 11/4", 11/2", 2",21/2", 3", 31/2", and 4" diameter trade size raceway in a rigid and secure manner as required by the 1990 National Electrical Code.
Since there does not exist a support bracket for this purpose, most electricians do not meet the code requirements in these installation of vertical raceway supports. Sometimes a conscientious electrician will manufacture a support at the job site in accordance with other structural members around the equipment of machine, if there are structural members available. Sometimes an electrician will construct a support and secure it to the machine electrical control cabinet.
The fashion and structure of these supports are typically one of a kind. For the electrician to build a support as just described he uses the following method:
1. Purchase material, angle iron or strut.
2. Cut, weld, drill, tap and fabricate together.
3. Attach the support to the control cabinet or structural member.
4. Prime and paint the newly constructed bracket. Painting is a requirement per the 1990 National Electrical Code, to provide corrosion protection.
5. Cutting, welding, drilling, tapping, and painting all require additional skills and complicate the installation time, increasing material, equipment and labor costs.
There is therefore a need to provide a single preformed conduit support bracket which has the capabilities of being bolted directly to a machine electrical control cabinet; is capable of supporting at least two vertical raceways, which may both be the same diameter or comprise of two different diameters; is capable of being field modified (bent) to accommodate at least one horizontal and one vertical raceway; is capable of accommodating trade size raceways ranging in the following diameters 1/2", 3/4", 1", 11/4", 11/2", 2", 21/2", 3", 31/2", and 4", with still a further capability of securing various types of raceways such as rigid metal conduit, rigid nonmetal conduit, intermediate metal conduit, liquidtight flexible conduit flexible metallic conduit, flexible metal conduit, electrical nonmetallic tubing, and electrical metallic tubing to the support bracket therefore complying with the three (3) and one (1) foot rule as outlined in the 1990 National Electrical Code.